From 16c7fa05829e8b91db48e3539c5d6ff3c2b18a23 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Tue, 30 Apr 2013 15:27:30 -0700 Subject: lib/string_helpers: introduce generic string_unescape There are several places in kernel where modules unescapes input to convert C-Style Escape Sequences into byte codes. The patch provides generic implementation of such approach. Test cases are also included into the patch. [akpm@linux-foundation.org: clarify comment] [akpm@linux-foundation.org: export get_random_int() to modules] Signed-off-by: Andy Shevchenko Cc: Samuel Thibault Cc: Greg Kroah-Hartman Cc: Jason Baron Cc: Alexander Viro Cc: William Hubbs Cc: Chris Brannon Cc: Kirk Reiser Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/string_helpers.h | 58 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 58 insertions(+) (limited to 'include/linux') diff --git a/include/linux/string_helpers.h b/include/linux/string_helpers.h index a3eb2f65b656..3eeee9672a4a 100644 --- a/include/linux/string_helpers.h +++ b/include/linux/string_helpers.h @@ -13,4 +13,62 @@ enum string_size_units { int string_get_size(u64 size, enum string_size_units units, char *buf, int len); +#define UNESCAPE_SPACE 0x01 +#define UNESCAPE_OCTAL 0x02 +#define UNESCAPE_HEX 0x04 +#define UNESCAPE_SPECIAL 0x08 +#define UNESCAPE_ANY \ + (UNESCAPE_SPACE | UNESCAPE_OCTAL | UNESCAPE_HEX | UNESCAPE_SPECIAL) + +/** + * string_unescape - unquote characters in the given string + * @src: source buffer (escaped) + * @dst: destination buffer (unescaped) + * @size: size of the destination buffer (0 to unlimit) + * @flags: combination of the flags (bitwise OR): + * %UNESCAPE_SPACE: + * '\f' - form feed + * '\n' - new line + * '\r' - carriage return + * '\t' - horizontal tab + * '\v' - vertical tab + * %UNESCAPE_OCTAL: + * '\NNN' - byte with octal value NNN (1 to 3 digits) + * %UNESCAPE_HEX: + * '\xHH' - byte with hexadecimal value HH (1 to 2 digits) + * %UNESCAPE_SPECIAL: + * '\"' - double quote + * '\\' - backslash + * '\a' - alert (BEL) + * '\e' - escape + * %UNESCAPE_ANY: + * all previous together + * + * Returns amount of characters processed to the destination buffer excluding + * trailing '\0'. + * + * Because the size of the output will be the same as or less than the size of + * the input, the transformation may be performed in place. + * + * Caller must provide valid source and destination pointers. Be aware that + * destination buffer will always be NULL-terminated. Source string must be + * NULL-terminated as well. + */ +int string_unescape(char *src, char *dst, size_t size, unsigned int flags); + +static inline int string_unescape_inplace(char *buf, unsigned int flags) +{ + return string_unescape(buf, buf, 0, flags); +} + +static inline int string_unescape_any(char *src, char *dst, size_t size) +{ + return string_unescape(src, dst, size, UNESCAPE_ANY); +} + +static inline int string_unescape_any_inplace(char *buf) +{ + return string_unescape_any(buf, buf, 0); +} + #endif -- cgit v1.2.3